Displays can be created from an array of light emitting devices each controlled by individual circuits (i.e., pixel circuits) having transistors for selectively controlling the circuits to be programmed with display information and to emit light according to the display information. Thin film transistors (“TFTs”) fabricated on a substrate can be incorporated into such displays. TFTs tend to demonstrate non-uniform behavior across display panels and over time as the displays age. Compensation techniques can be applied to such displays to achieve image uniformity across the displays and to account for degradation in the displays as the displays age.
Some schemes for providing compensation to displays to account for variations across the display panel and over time utilize monitoring systems to measure time dependent parameters associated with the aging (i.e., degradation) and/or fabrication of the pixel circuits. The measured information can then be used to inform subsequent programming of the pixel circuits so as to ensure that any measured degradation is accounted for by adjustments made to the programming. Such monitored pixel circuits may require the use of additional transistors and/or lines to selectively couple the pixel circuits to the monitoring systems and provide for reading out information. The incorporation of additional transistors and/or lines may undesirably decrease pixel-pitch (i.e., “pixel density”).